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  <xsd:element id="clh_AnticipatedPaymentForAssetRetirementObligationsYearFour" name="AnticipatedPaymentForAssetRetirementObligationsYearFour" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_AnticipatedPaymentForAssetRetirementObligationsYearOne" name="AnticipatedPaymentForAssetRetirementObligationsYearOne" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_AnticipatedPaymentForAssetRetirementObligationsYearThree" name="AnticipatedPaymentForAssetRetirementObligationsYearThree" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_AnticipatedPaymentForAssetRetirementObligationsYearTwo" name="AnticipatedPaymentForAssetRetirementObligationsYearTwo" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
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  <xsd:element abstract="true" id="clh_BankOfMontrealMember" name="BankOfMontrealMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_BatonRougeLaMember" name="BatonRougeLaMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_BreslubePennSiteMember" name="BreslubePennSiteMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_BridgeportNjMember" name="BridgeportNjMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_BusinessAcquisitionAcquireesObligationToReimburseOutOfPocketExpensesAmount" name="BusinessAcquisitionAcquireesObligationToReimburseOutOfPocketExpensesAmount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_BusinessAcquisitionCostOfAcquiredEntityPurchasePriceMeasurementAdjustment" name="BusinessAcquisitionCostOfAcquiredEntityPurchasePriceMeasurementAdjustment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_BusinessAcquisitionMinimumAffirmativePercentageOfAcquireesShareholdersVoteRequiredForAcquisitionApproval" name="BusinessAcquisitionMinimumAffirmativePercentageOfAcquireesShareholdersVoteRequiredForAcquisitionApproval" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_BusinessAcquisitionNumberOfEmployeesOfAcquireeEntity" name="BusinessAcquisitionNumberOfEmployeesOfAcquireeEntity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_BusinessAcquisitionOutOfPocketExpensesReimbursedByAcquiree" name="BusinessAcquisitionOutOfPocketExpensesReimbursedByAcquiree" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_BusinessAcquisitionPercentageOwnershipOfAcquireePriorToAcquisition" name="BusinessAcquisitionPercentageOwnershipOfAcquireePriorToAcquisition" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_BusinessAcquisitionProFormaCombinedInformationTableTextBlock" name="BusinessAcquisitionProFormaCombinedInformationTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_BusinessAcquisitionPurchasePriceAllocationAssetRetirementObligationsAndRemedialLiabilities" name="BusinessAcquisitionPurchasePriceAllocationAssetRetirementObligationsAndRemedialLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalentsAssumedForDebtRepayment" name="BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCashAndCashEquivalentsAssumedForDebtRepayment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
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  <xsd:element id="clh_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCustomerReceivablesGrossAmountDue" name="BusinessAcquisitionPurchasePriceAllocationCurrentAssetsCustomerReceivablesGrossAmountDue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
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  <xsd:element abstract="true" id="clh_CampEquipmentMember" name="CampEquipmentMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_CanadaMember" name="CanadaMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_CanadianCorporateSecuritiesAndOtherBondsMember" name="CanadianCorporateSecuritiesAndOtherBondsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
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  <xsd:element abstract="true" id="clh_CashPaymentsForInterestAndIncomeTaxesAbstract" name="CashPaymentsForInterestAndIncomeTaxesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_CasmaliaSiteMember" name="CasmaliaSiteMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
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  <xsd:element abstract="true" id="clh_ChangeInTaxBenefitsMember" name="ChangeInTaxBenefitsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
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  <xsd:element abstract="true" id="clh_CommercialLandfillsMember" name="CommercialLandfillsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ConcentrationRiskMajorCustomersOverBenchmark" name="ConcentrationRiskMajorCustomersOverBenchmark" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_CondensedConsolidatingBalanceSheetLineItems" name="CondensedConsolidatingBalanceSheetLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_CondensedConsolidatingStatementsOfCashFlowsLineItems" name="CondensedConsolidatingStatementsOfCashFlowsLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_CondensedConsolidatingStatementsOfOperationsLineItems" name="CondensedConsolidatingStatementsOfOperationsLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_CondensedFinancialInformationForSubsidiaryGuarantorsAndNonGuarantorsDisclosureTextBlock" name="CondensedFinancialInformationForSubsidiaryGuarantorsAndNonGuarantorsDisclosureTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ConsumedAirspace" name="ConsumedAirspace" nillable="true" substitutionGroup="xbrli:item" type="num:volumeItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ContingenciesByNatureOfContingencyAxis" name="ContingenciesByNatureOfContingencyAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
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  <xsd:element id="clh_CreditAdjustedRiskFreeRate" name="CreditAdjustedRiskFreeRate" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_CreditConcentrationPolicyTextBlock" name="CreditConcentrationPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
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  <xsd:element abstract="true" id="clh_DebtInstrumentVariableRateBaseAxis" name="DebtInstrumentVariableRateBaseAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
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  <xsd:element abstract="true" id="clh_DebtInstrumentVariableRateBaseOnBaseRateLoansMember" name="DebtInstrumentVariableRateBaseOnBaseRateLoansMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_DebtInstrumentVariableRateBaseOnLiborLoansMember" name="DebtInstrumentVariableRateBaseOnLiborLoansMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_DebtPayableToAffiliatesSubsidiariesAndHoldingCompanies" name="DebtPayableToAffiliatesSubsidiariesAndHoldingCompanies" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_DebtReceivableFromAffiliatesSubsidiariesAndHoldingCompanies" name="DebtReceivableFromAffiliatesSubsidiariesAndHoldingCompanies" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_DeductibleHealthInsurancePolicy" name="DeductibleHealthInsurancePolicy" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_DeductiblePerOccurrenceForWorkersCompensationGeneralLiabilityAndVehicleLiability" name="DeductiblePerOccurrenceForWorkersCompensationGeneralLiabilityAndVehicleLiability" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_DeerParkMember" name="DeerParkMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_DeerTrailColoradoFacilityMember" name="DeerTrailColoradoFacilityMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_DeerTrailMember" name="DeerTrailMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_DeferredIncomeTaxExpenseBenefitNetOfDiscontinuedOperations" name="DeferredIncomeTaxExpenseBenefitNetOfDiscontinuedOperations" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_DeferredTaxAssetsAccruedCompensation" name="DeferredTaxAssetsAccruedCompensation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_DeferredTaxAssetsAccruedExpenses" name="DeferredTaxAssetsAccruedExpenses" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_DeferredTaxAssetsClosurePostClosureAndRemedialLiabilities" name="DeferredTaxAssetsClosurePostClosureAndRemedialLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_DeferredTaxAssetsStockBasedCompensation" name="DeferredTaxAssetsStockBasedCompensation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_DeferredTaxAssetsUncertainTaxPositionsAccruedInterestAndFederalBenefit" name="DeferredTaxAssetsUncertainTaxPositionsAccruedInterestAndFederalBenefit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_DeferredTaxLiabilitiesGross" name="DeferredTaxLiabilitiesGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_DeferredTaxLiabilitiesPropertyPlantAndEquipmentIncreaseDecrease" name="DeferredTaxLiabilitiesPropertyPlantAndEquipmentIncreaseDecrease" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_DeferredTaxLiabilitiespermitsAndCustomerDatabase" name="DeferredTaxLiabilitiespermitsAndCustomerDatabase" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_DefinedBenefitPlanAssumptionsUsedInCalculatingBenefitObligationAdjustmentForInvestmentAndCustodialFees" name="DefinedBenefitPlanAssumptionsUsedInCalculatingBenefitObligationAdjustmentForInvestmentAndCustodialFees" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
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  <xsd:element abstract="true" id="clh_DefinedContributionPlanDomain" name="DefinedContributionPlanDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_DefinedContributionPlanLineItems" name="DefinedContributionPlanLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_DefinedContributionPlanTable" name="DefinedContributionPlanTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_DenominatorForBasicAndDilutedEarningsPerShareAbstract" name="DenominatorForBasicAndDilutedEarningsPerShareAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_DiscountReserves" name="DiscountReserves" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_DistributionsEarnedOnEmployeeParticipationPlan" name="DistributionsEarnedOnEmployeeParticipationPlan" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_DividendsPaid" name="DividendsPaid" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_DividendsPaidReceived" name="DividendsPaidReceived" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_DocumentAndEntityInformationabstract" name="DocumentAndEntityInformationabstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_EffectiveIncomeTaxRate" name="EffectiveIncomeTaxRate" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_EmployeeParticipationPlanAxis" name="EmployeeParticipationPlanAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_EmployeeStockPurchasePlan2005Member" name="EmployeeStockPurchasePlan2005Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_EnvironmentalContingenciesTable" name="EnvironmentalContingenciesTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_EvereadysParticipationPlanMember" name="EvereadysParticipationPlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ExpectedReturnOnFairValueOfAssets" name="ExpectedReturnOnFairValueOfAssets" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ExpenseRecognizedInOtherComprehensiveIncome" name="ExpenseRecognizedInOtherComprehensiveIncome" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_ExpirationOfVariousStateStatuteOfLimitation" name="ExpirationOfVariousStateStatuteOfLimitation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ExpiringStatuteOfLimitationsRelatedToHistoricalCanadianBusinessCombination" name="ExpiringStatuteOfLimitationsRelatedToHistoricalCanadianBusinessCombination" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ExplorationServicesMember" name="ExplorationServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_FacilitiesUnderValidlyIssuedPermit" name="FacilitiesUnderValidlyIssuedPermit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_FederalAndStateEnforcementActionsAbstract" name="FederalAndStateEnforcementActionsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_FederalAndStateEnforcementActionsMember" name="FederalAndStateEnforcementActionsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_FieldServicesMember" name="FieldServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ForeignTaxCreditThereafterMember" name="ForeignTaxCreditThereafterMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ForeignTaxCreditYearFiveMember" name="ForeignTaxCreditYearFiveMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ForeignTaxCreditYearFourMember" name="ForeignTaxCreditYearFourMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ForeignTaxCreditYearOneMember" name="ForeignTaxCreditYearOneMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ForeignTaxCreditYearThreeMember" name="ForeignTaxCreditYearThreeMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ForeignTaxCreditYearTwoMember" name="ForeignTaxCreditYearTwoMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_GainLossOnSaleOfFixedAssetsAndAssetsHeldForSale" name="GainLossOnSaleOfFixedAssetsAndAssetsHeldForSale" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_GainOnSalesOfBusinesses" name="GainOnSalesOfBusinesses" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_GrassyMountainMember" name="GrassyMountainMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_GuarantorAndNonGuarantorSubsidiariesFinancialInformationAbstract" name="GuarantorAndNonGuarantorSubsidiariesFinancialInformationAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_GulfOfMexicoAndMichiganMember" name="GulfOfMexicoAndMichiganMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_GulfOfMexicoMember" name="GulfOfMexicoMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_IdledIncineratorAndLegalProceedingsMember" name="IdledIncineratorAndLegalProceedingsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ImputedInterestMinimim" name="ImputedInterestMinimim" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ImputedInterestRate" name="ImputedInterestRate" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_ImputedInterestRateMaximum" name="ImputedInterestRateMaximum" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_InactiveLandfillFacilitiesMember" name="InactiveLandfillFacilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_IncinerationFacilitiesMember" name="IncinerationFacilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_IncomeLossFromAffiliatesSubsidiariesAndHoldingCompany" name="IncomeLossFromAffiliatesSubsidiariesAndHoldingCompany" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAndIncomeFromDiscountinuedOperations" name="IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestmentsAndIncomeFromDiscountinuedOperations" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_IncomeLossFromContinuingOperationsBeforeInterestTaxDepreciationAndAmortizationNet" name="IncomeLossFromContinuingOperationsBeforeInterestTaxDepreciationAndAmortizationNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_IncomeTaxExpenseBenefitNetOfDiscountinuedOperations" name="IncomeTaxExpenseBenefitNetOfDiscountinuedOperations" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_IncreaseDecreadeTaxBenefitFromStockOptionsExercised" name="IncreaseDecreadeTaxBenefitFromStockOptionsExercised" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_IndustrialServicesMember" name="IndustrialServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_InflationRate" name="InflationRate" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_IntangibleAssetsNetExcludingGoodwillPercent" name="IntangibleAssetsNetExcludingGoodwillPercent" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_IntangibleAssetsNetIncludingGoodwill" name="IntangibleAssetsNetIncludingGoodwill" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_InterestExpenseNet" name="InterestExpenseNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_InternationalEquitySecuritiesMember" name="InternationalEquitySecuritiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_KimballMember" name="KimballMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_LambtonMember" name="LambtonMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LandFillAccountingPolicyTextBlock" name="LandFillAccountingPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LandfillFinalClosureAndPostClosureLiabilities" name="LandfillFinalClosureAndPostClosureLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_LandfillRetirementLiabilityMember" name="LandfillRetirementLiabilityMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LandfillSites" name="LandfillSites" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_LastDayOfQuarterlyOfferingMember" name="LastDayOfQuarterlyOfferingMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LeaseTermsRangeMaximum" name="LeaseTermsRangeMaximum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LeaseTermsRangeMinimum" name="LeaseTermsRangeMinimum" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_LegalAndAdministrativeProceedingsAbstract" name="LegalAndAdministrativeProceedingsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_LegalAndAdministrativeProceedingsMember" name="LegalAndAdministrativeProceedingsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LettersOfCreditPolicyTextBlock" name="LettersOfCreditPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LineOfCreditFacilityBorrowingCapacity" name="LineOfCreditFacilityBorrowingCapacity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LineOfCreditFacilityNumberOfSubsidiariesAddedAsParty" name="LineOfCreditFacilityNumberOfSubsidiariesAddedAsParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_LoneMountainMember" name="LoneMountainMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_LongLivedAssetsByNameAxis" name="LongLivedAssetsByNameAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_LongLivedAssetsByNameDomain" name="LongLivedAssetsByNameDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtPurchasePriceForPurposesOfResaleAsPercentageOfPrincipalAmount" name="LongTermDebtPurchasePriceForPurposesOfResaleAsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtPurchasePriceForPurposesOfResaleEffectiveYieldToMaturity" name="LongTermDebtPurchasePriceForPurposesOfResaleEffectiveYieldToMaturity" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionOnOrAfterSeptember2011ButPriorToAugust2012AsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionOnOrAfterSeptember2011ButPriorToAugust2012AsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionPriceAsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionPriceAsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionPriceDueToChangeOfControlAsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionPriceDueToChangeOfControlAsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionPriceDueToSalesOfCertainAssetsAsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionPriceDueToSalesOfCertainAssetsAsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionPriceDuringTwelveMonthPeriodCommencingOnAugust2012AsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionPriceDuringTwelveMonthPeriodCommencingOnAugust2012AsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionPriceDuringTwelveMonthPeriodCommencingOnAugust2013AsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionPriceDuringTwelveMonthPeriodCommencingOnAugust2013AsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionPriceDuringTwelveMonthPeriodCommencingOnAugust2014AndThereAfterAsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionPriceDuringTwelveMonthPeriodCommencingOnAugust2014AndThereAfterAsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionPriceOnOrAfterSeptember2011ButPriorToAugust2012AsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionPriceOnOrAfterSeptember2011ButPriorToAugust2012AsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionPriceWithNetProceedsFromEquityOfferingsAsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionPriceWithNetProceedsFromEquityOfferingsAsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LongTermDebtRedemptionWithNetProceedsFromEquityOfferingsAsPercentageOfPrincipalAmount" name="LongTermDebtRedemptionWithNetProceedsFromEquityOfferingsAsPercentageOfPrincipalAmount" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_LossContingencyAccrualAtCarryingValuePotentialAdditionalLiability" name="LossContingencyAccrualAtCarryingValuePotentialAdditionalLiability" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_LossContingencyActionsTakenByPlaintiffValue" name="LossContingencyActionsTakenByPlaintiffValue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_LossContingencyRangeOfLoss" name="LossContingencyRangeOfLoss" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_MarineShaleSiteMember" name="MarineShaleSiteMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_MercierQuebecMember" name="MercierQuebecMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_MexicoMember" name="MexicoMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_MobileIndustrialHealthBusinessMember" name="MobileIndustrialHealthBusinessMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NetDividendIncomeFromAffiliatesSubsidiariesAndHoldingCompany" name="NetDividendIncomeFromAffiliatesSubsidiariesAndHoldingCompany" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_NetInterestIncomeFromAffiliatesSubsidiariesAndHoldingCompany" name="NetInterestIncomeFromAffiliatesSubsidiariesAndHoldingCompany" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_NonCommercialLandfillsMember" name="NonCommercialLandfillsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NonLandfillClosureAndPostClosureLiabilities" name="NonLandfillClosureAndPostClosureLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_NonLandfillClosureAndPostClosureLiabilitiesPolicyTextBlock" name="NonLandfillClosureAndPostClosureLiabilitiesPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_NonLandfillRetirementLiabilityMember" name="NonLandfillRetirementLiabilityMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NumberOfActiveNonSupervisoryCanadianEmployees" name="NumberOfActiveNonSupervisoryCanadianEmployees" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_NumberOfExpansions" name="NumberOfExpansions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NumberOfNeighboringMunicipalitiesFilingSeparateLegalProceedings" name="NumberOfNeighboringMunicipalitiesFilingSeparateLegalProceedings" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NumberOfOperationsNotManagedByReportableSegments" name="NumberOfOperationsNotManagedByReportableSegments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NumberOfPermitsIssuedByGovernmentToDumpOrganicLiquid" name="NumberOfPermitsIssuedByGovernmentToDumpOrganicLiquid" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_NumberOfProvincesInWhichEntityOperates" name="NumberOfProvincesInWhichEntityOperates" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_NumberOfServiceLocations" name="NumberOfServiceLocations" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_NumberOfTermLoanFacilities" name="NumberOfTermLoanFacilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_NumberOfTotalMunicipalitiesFilingSeparateLegalProceedings" name="NumberOfTotalMunicipalitiesFilingSeparateLegalProceedings" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_NumeratorForBasicAndDilutedEarningsPerShareAbstract" name="NumeratorForBasicAndDilutedEarningsPerShareAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_OilAndGasFieldServicesMember" name="OilAndGasFieldServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_OpenTreatmentStorageOrDisposalFacilitiesMember" name="OpenTreatmentStorageOrDisposalFacilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_OperatingSegmentsNumber" name="OperatingSegmentsNumber" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_OtherContingenciesAbstract" name="OtherContingenciesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_OtherContingenciesMember" name="OtherContingenciesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_OtherForeignMember" name="OtherForeignMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ParticipationPlanAsEquityAwardAndRecognizedCompensation" name="ParticipationPlanAsEquityAwardAndRecognizedCompensation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ParticipationPlanDomain" name="ParticipationPlanDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_PayablesToAffiliatesSubsidiariesAndHoldingCompanies" name="PayablesToAffiliatesSubsidiariesAndHoldingCompanies" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_PaymentCommencingInYear6SecuredByBothPurchasedAndMatchingUnits" name="PaymentCommencingInYear6SecuredByBothPurchasedAndMatchingUnits" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_PaymentsForProceedsFromInterest" name="PaymentsForProceedsFromInterest" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_PaymentsOfPrincipalOnDebt" name="PaymentsOfPrincipalOnDebt" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_PaymentsToAcquireMinorityInterestInPrivatelyHeldCompany" name="PaymentsToAcquireMinorityInterestInPrivatelyHeldCompany" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_PayrollDeductionToPurchaseCommonStock" name="PayrollDeductionToPurchaseCommonStock" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_PeakEnergyServicesLtdSPeakMember" name="PeakEnergyServicesLtdSPeakMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_PerShareShortfallBonus" name="PerShareShortfallBonus" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_PercentageOfAirspaceRemaining" name="PercentageOfAirspaceRemaining" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_PercentageOfMatchingUnitsVestingEachDecember31From2001To2011" name="PercentageOfMatchingUnitsVestingEachDecember31From2001To2011" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_PerformanceEvaluationStockBasedCompensation" name="PerformanceEvaluationStockBasedCompensation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_PerformanceStockAwardsMember" name="PerformanceStockAwardsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_PeriodFacilitySatIdled" name="PeriodFacilitySatIdled" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_PermitsMember" name="PermitsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_PermittedButNotHighlyProbableAirspace" name="PermittedButNotHighlyProbableAirspace" nillable="true" substitutionGroup="xbrli:item" type="num:volumeItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_PermittedMember" name="PermittedMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_PolychlorinatedBiphenylsManagementAndOilStorageAndRecyclingMember" name="PolychlorinatedBiphenylsManagementAndOilStorageAndRecyclingMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_PotentialShortfallBonus" name="PotentialShortfallBonus" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_PrepaidExpensesAndOtherAssetsCurrent" name="PrepaidExpensesAndOtherAssetsCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_PrepaidExpensesAndOtherAssetsCurrentIncrease" name="PrepaidExpensesAndOtherAssetsCurrentIncrease" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_PriorLineOfCreditMember" name="PriorLineOfCreditMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ProbableAirspace" name="ProbableAirspace" nillable="true" substitutionGroup="xbrli:item" type="num:volumeItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_ProceedsFromInsuranceSettlement" name="ProceedsFromInsuranceSettlement" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_ProceedsFromIntercompanyDebt" name="ProceedsFromIntercompanyDebt" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_ProceedsFromIntercompanyFinancing" name="ProceedsFromIntercompanyFinancing" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_ProceedsFromSalesOfFixedAssetsAndAssetsHeldForSale" name="ProceedsFromSalesOfFixedAssetsAndAssetsHeldForSale" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_ProceedsFromWarrantExercise" name="ProceedsFromWarrantExercise" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_PropertyPlantAndEquipmentDepreciationAndAmortization" name="PropertyPlantAndEquipmentDepreciationAndAmortization" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_PropertyPlantAndEquipmentNetPercent" name="PropertyPlantAndEquipmentNetPercent" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_QuarterlyDataUnauditedAbstract" name="QuarterlyDataUnauditedAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_QuarterlyDataUnauditedUnauditedTextBlock" name="QuarterlyDataUnauditedUnauditedTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_QuarterlyOfferingsOfShares" name="QuarterlyOfferingsOfShares" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_QuarterlyOfferingsOfSharesMember" name="QuarterlyOfferingsOfSharesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_QuarteryDataUnauditedTableTextBlock" name="QuarteryDataUnauditedTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ReceivablesFromAffiliatesSubsidiariesAndHoldingCompanies" name="ReceivablesFromAffiliatesSubsidiariesAndHoldingCompanies" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_ReconciliationOfNetIncomeToAdjustedEbitdaAbstract" name="ReconciliationOfNetIncomeToAdjustedEbitdaAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RedeemableDebtInstrumentAmount" name="RedeemableDebtInstrumentAmount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_RedeemableDebtRedemptionAxis" name="RedeemableDebtRedemptionAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_RedeemableDebtRedemptionDomain" name="RedeemableDebtRedemptionDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_RedeemableDebtRedemptionRateOf103PercentMember" name="RedeemableDebtRedemptionRateOf103PercentMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_RedeemableDebtRedemptionRateOf107625PercentMember" name="RedeemableDebtRedemptionRateOf107625PercentMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RegulatoryPostClosurePeriodForLandfill" name="RegulatoryPostClosurePeriodForLandfill" nillable="true" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RemainingHighlyProbableAirspace" name="RemainingHighlyProbableAirspace" nillable="true" substitutionGroup="xbrli:item" type="num:volumeItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RemainingHighlyProbableAirspaceTableTextBlock" name="RemainingHighlyProbableAirspaceTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RemedialLiabilitiesAnticipatedPaymentsForEachOfNextFiveYearsTableTextBlock" name="RemedialLiabilitiesAnticipatedPaymentsForEachOfNextFiveYearsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RemedialLiabilitiesDiscountedRiskFreeInterestRate" name="RemedialLiabilitiesDiscountedRiskFreeInterestRate" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_RemedialLiabilitiesForInactiveSitesMember" name="RemedialLiabilitiesForInactiveSitesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_RemedialLiabilitiesForLandfillSitesMember" name="RemedialLiabilitiesForLandfillSitesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_RemedialLiabilitiesIncludingSuperfundForNonLandfillOperationsMember" name="RemedialLiabilitiesIncludingSuperfundForNonLandfillOperationsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RemedialLiabilitiesInflationRateAtAcquistion" name="RemedialLiabilitiesInflationRateAtAcquistion" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_RententionForEnviromentalImpairment" name="RententionForEnviromentalImpairment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_RepaymentOfCapitalLeaseObligation" name="RepaymentOfCapitalLeaseObligation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_ReportingSegmentsNumber" name="ReportingSegmentsNumber" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ReservesToBeProvidedOverRemainingSiteLives" name="ReservesToBeProvidedOverRemainingSiteLives" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_RyleyMember" name="RyleyMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SanJoseCaMember" name="SanJoseCaMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SawyerMember" name="SawyerMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ScheduleIiAbstract" name="ScheduleIiAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfCondensedConsolidatingBalanceSheetTableTextBlock" name="ScheduleOfCondensedConsolidatingBalanceSheetTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfCondensedConsolidatingStatementOfCashFlowsTableTextBlock" name="ScheduleOfCondensedConsolidatingStatementOfCashFlowsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfCondensedConsolidatingStatementOfOperationsTableTextBlock" name="ScheduleOfCondensedConsolidatingStatementOfOperationsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfDebtInstrumentRedemptionPriceTableTextBlock" name="ScheduleOfDebtInstrumentRedemptionPriceTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfExpectedPaymentsRelatedToAssetRetirementObligationsTableTextBlock" name="ScheduleOfExpectedPaymentsRelatedToAssetRetirementObligationsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfFurtureMinimumLeasePaymenstForCapitalLeasesAndOperatingLeasesTableTextBlock" name="ScheduleOfFurtureMinimumLeasePaymenstForCapitalLeasesAndOperatingLeasesTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfPropertyPlantAndEquipmentLandfillAssetsTableTextBlock" name="ScheduleOfPropertyPlantAndEquipmentLandfillAssetsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfReconciliationOfNetIncomeToAdjustedEarningsBeforeInterestTaxDepreciationAndAmortizationConsolidatedTableTextBlock" name="ScheduleOfReconciliationOfNetIncomeToAdjustedEarningsBeforeInterestTaxDepreciationAndAmortizationConsolidatedTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfSegmentPpeAndIntangibleAssetsTableTextBlock" name="ScheduleOfSegmentPpeAndIntangibleAssetsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfSegmentRevenuesTableTextBlock" name="ScheduleOfSegmentRevenuesTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfSegmentTotalAssetsTableTextBlock" name="ScheduleOfSegmentTotalAssetsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ScheduleOfServiceLocationInformationTable" name="ScheduleOfServiceLocationInformationTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ScheduleOfTotalAssetsByGeographicalAreaTableTextBlock" name="ScheduleOfTotalAssetsByGeographicalAreaTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SegmentReportingInformationRevenuePercent" name="SegmentReportingInformationRevenuePercent" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SelfInsuranceDiscountRate" name="SelfInsuranceDiscountRate" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_SelfInsuranceLiabilities" name="SelfInsuranceLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="clh_SelfInsuranceLiabilitiesAnticipatedPaymentsTableTextBlock" name="SelfInsuranceLiabilitiesAnticipatedPaymentsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ServiceCentersSatelliteAndSupportLocationsCorporateAndRegionalOfficesMember" name="ServiceCentersSatelliteAndSupportLocationsCorporateAndRegionalOfficesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ServiceLocationsByTypeAxis" name="ServiceLocationsByTypeAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ServiceLocationsByTypeAxisDomain" name="ServiceLocationsByTypeAxisDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_ServiceLocationsByTypeLineItems" name="ServiceLocationsByTypeLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalSharesAuthorized" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalSharesAuthorized" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="instant" />
  <xsd:element id="clh_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedForfeitureRateEmployees" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedForfeitureRateEmployees" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedForfeitureRatesExecutivesDirectors" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedForfeitureRatesExecutivesDirectors" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SharesHeldUnderEmployeeParticipationPlan" name="SharesHeldUnderEmployeeParticipationPlan" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SharesHeldUnderEmployeeParticipationPlanMember" name="SharesHeldUnderEmployeeParticipationPlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SignificantAccountingPoliciesAbstract" name="SignificantAccountingPoliciesAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SignificantAccountingPoliciesAccumulatedOtherComprehensiveIncomeAbstract" name="SignificantAccountingPoliciesAccumulatedOtherComprehensiveIncomeAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SignificantAccountingPoliciesAndRecentAccountingPronouncementsTextBlock" name="SignificantAccountingPoliciesAndRecentAccountingPronouncementsTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SignificantAccountingPoliciesBusinessCombinationsAbstract" name="SignificantAccountingPoliciesBusinessCombinationsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SignificantChangeInUnrecognizedTaxBenefitsIncludingInterestAndPenaltiesIsReasonablyPossibleAmountOfUnrecordedBenefit" name="SignificantChangeInUnrecognizedTaxBenefitsIncludingInterestAndPenaltiesIsReasonablyPossibleAmountOfUnrecordedBenefit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_SignificantPurchaseCommitmentAmountCommittedOutstanding" name="SignificantPurchaseCommitmentAmountCommittedOutstanding" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_SiteContingencyAreaAcquiredByEntity" name="SiteContingencyAreaAcquiredByEntity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyCleanupCostsNumberOfSitesOwnedByThirdParty" name="SiteContingencyCleanupCostsNumberOfSitesOwnedByThirdParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty" name="SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdPartyContestedByEntity" name="SiteContingencyEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdPartyContestedByEntity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyEnvironmentalRemediationExpenseSettledNumberOfSitesOwnedByThirdParty" name="SiteContingencyEnvironmentalRemediationExpenseSettledNumberOfSitesOwnedByThirdParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyEpaInformationRequestReceivedNumberOfSitesOwnedByThirdParty" name="SiteContingencyEpaInformationRequestReceivedNumberOfSitesOwnedByThirdParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyIndemnificationAgreementNumberOfSitesOwnedByThirdParty" name="SiteContingencyIndemnificationAgreementNumberOfSitesOwnedByThirdParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyNotRequiringEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty" name="SiteContingencyNotRequiringEnvironmentalRemediationExpenseNumberOfSitesOwnedByThirdParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyNoticeReceivedNumberOfSitesOwnedByThirdParty" name="SiteContingencyNoticeReceivedNumberOfSitesOwnedByThirdParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyNumberOfSites" name="SiteContingencyNumberOfSites" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyNumberOfSitesOwnedByEntity" name="SiteContingencyNumberOfSitesOwnedByEntity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyNumberOfSitesOwnedByThirdParty" name="SiteContingencyNumberOfSitesOwnedByThirdParty" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyNumberOfSitesOwnedByThirdPartyExcludedFromCleanupOrRelatedLiabilities" name="SiteContingencyNumberOfSitesOwnedByThirdPartyExcludedFromCleanupOrRelatedLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_SiteContingencyRemainingReserves" name="SiteContingencyRemainingReserves" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_SolarEquipmentMember" name="SolarEquipmentMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SolventRecyclingFacilitiesMember" name="SolventRecyclingFacilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_StockIssuedDuringPeriodSharesStockWarrantsExercised" name="StockIssuedDuringPeriodSharesStockWarrantsExercised" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_StockIssuedDuringPeriodValueStockWarrantsExercised" name="StockIssuedDuringPeriodValueStockWarrantsExercised" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_StockSplitsPolicyTextBlock" name="StockSplitsPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SummaryOfRecognisedAmountsOfIdentifiableAssetsAndLiabilitiesAssumedRollForward" name="SummaryOfRecognisedAmountsOfIdentifiableAssetsAndLiabilitiesAssumedRollForward" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SuperfundLandfillSitesOwnedByThirdPartiesMember" name="SuperfundLandfillSitesOwnedByThirdPartiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SuperfundProceedingsAbstract" name="SuperfundProceedingsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_SuperfundProceedingsMember" name="SuperfundProceedingsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_TechnicalServicesMember" name="TechnicalServicesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_TreatmentStorageAndDisposalFacilitiesMember" name="TreatmentStorageAndDisposalFacilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_UnbilledAccountsReceivableCurrent" name="UnbilledAccountsReceivableCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_UncertainTaxPositionInterestAndPenaltiesNetOfBenefit" name="UncertainTaxPositionInterestAndPenaltiesNetOfBenefit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_UncertainTaxPositionReleasesNetOfBenefit" name="UncertainTaxPositionReleasesNetOfBenefit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="clh_UndiscountedClosureAndPostClosureLiabilities" name="UndiscountedClosureAndPostClosureLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_UndiscountedSelfInsuranceLiabilities" name="UndiscountedSelfInsuranceLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_UndistributedEarningsOfForeignSubsidiaries" name="UndistributedEarningsOfForeignSubsidiaries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_UnfundedPensionLiabilityDeferredTaxes" name="UnfundedPensionLiabilityDeferredTaxes" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_UnitedStatesAndPuertoRicoMember" name="UnitedStatesAndPuertoRicoMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_UnitedStatesDefinedContributionPlanMember" name="UnitedStatesDefinedContributionPlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_UnitedStatesEquitySecuritiesMember" name="UnitedStatesEquitySecuritiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_UnitedStatesMember" name="UnitedStatesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_UnpermittedMember" name="UnpermittedMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_UnrecognizedTaxBenefitsAndOtherLongTermLiabilitiesNoncurrent" name="UnrecognizedTaxBenefitsAndOtherLongTermLiabilitiesNoncurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_UnrecognizedTaxBenefitsIncludingInterestAndPenalties" name="UnrecognizedTaxBenefitsIncludingInterestAndPenalties" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_ValuationAllowanceAmountForeignNetOperatingLoss" name="ValuationAllowanceAmountForeignNetOperatingLoss" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="clh_ValuationAllowanceAmountForeignTaxCredits" name="ValuationAllowanceAmountForeignTaxCredits" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="clh_ValuationAllowanceAmountStateNetOperatingLoss" name="ValuationAllowanceAmountStateNetOperatingLoss" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_VariousMember" name="VariousMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_VehiclesGross" name="VehiclesGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="clh_VilleMercierMember" name="VilleMercierMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_WasteFacilitiesMember" name="WasteFacilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_WastewaterTreatmentFacilitiesMember" name="WastewaterTreatmentFacilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_WeightedAveragePerShareFairValuesOfPurchaseRights" name="WeightedAveragePerShareFairValuesOfPurchaseRights" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_WestmorlandMember" name="WestmorlandMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_WichitaPropertyMember" name="WichitaPropertyMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="clh_WriteOffDeferredFinancingCostsAndDebtDiscount" name="WriteOffDeferredFinancingCostsAndDebtDiscount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="clh_YellowstoneRiverMember" name="YellowstoneRiverMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
</xsd:schema>